Newsletter - April 2006

Note: The following summaries are based on articles from the press and from peer-reviewed publications, and they represent the opinions of the original authors. The views of authors expressed herein do not necessarily state or reflect those of the United States Government, and shall not be used for advertising or product endorsement purposes. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government.

Recent Advisory News

Mercury levels remain high in many fish. VIRGINIA -- Virginia Department of Environmental Quality (DEQ) reported that mercury found in many fish species from the South River remained unchanged from 2002 through 2005. The department tested smallmouth bass, white sucker, rainbow trout and redbreast sunfish in the spring of last year. The mercury levels averaged from 0.5 to 1.5 parts per million. The high levels mean fish consumption advisories from the Virginia Department of Health will remain unchanged. Officials say it is safe to eat stocked fish from the South Fork of the Shenandoah River; however the remaining reaches have advisories. From Port Republic to Front Royal, people should eat no more than two meals of fish per month from the South Fork. North of Front Royal, carp, channel catfish and white sucker from the South Fork of the Shenandoah and Shenandoah rivers should not be eaten due to a PCB advisory, and no more than two meals per month of other species should be eaten.

Source: Harrisonburg Daily News Record, - March 10, 2006

Eating fish, game from river can boost dioxin exposure, state warns: Pamphlet warns residents near Tittabawassee flood plain of health dangers. Detroit, MI -- Michigan Department of Environmental Quality (DEQ) contacted about 500 people living along the Tittabawassee river because of historic dioxin contamination. DEQ warns that regularly eating fish and game from the Tittabawassee River can dramatically increase dioxin exposure. For example, by eating walleye for dinner one night and deer the next night once a month, a riverside resident would increase dioxin exposure 320 percent over what the average adult experiences, even if the person heeded every state precaution for avoiding contact with the dioxin contaminated soil. In addition, altering the diet to one meal of catfish and another of deer, deer liver or wild turkey and the exposure rises 1,000 percent higher than that of the average adult. Under the worst-case scenario: where a person eats seven meals of sport fish from the Tittabawassee River a month, a diet that also would include bottom-feeders such as catfish and carp, and ignores all recommendations for avoiding dioxin, that person would increase exposure to dioxin by 3,900 percent.

Source: The Detroit News, - March 11, 2006

Mercury warning issued for fish in Gulf, other sites. Baton Rouge, LA -- A new mercury advisory from the state warns women of childbearing age and children under the age of seven should not eat any king mackerel caught in the Gulf of Mexico. Sampled mercury levels in fish led state agencies to announce that people should limit consumption of fish taken out of certain Louisiana water bodies, including the Gulf of Mexico. State officials also recommended that young women and children not eat more than one half-pound meal per month of Gulf-caught cobia, blackfin tuna or greater amberjack. In addition to the extensions of the Gulf advisory and an advisory for Bayou Dorcheat in Webster Parish, state agencies added four new water bodies to the advisory list. New advisories have been issued for Black Bayou Lake in Caddo Parish, Lake Bistineau in northwest Louisiana, Iatt Lake in Grant Parish and Bayou Chene/Bayou Lacassine in Southwest Louisiana.

Source: KLFY - March 13, 2006

Test of women's hair finds high mercury levels. Patch's study (released last month), which is co-sponsored by the San Francisco-based Sierra Club and the Washington-based Greenpeace, tested mercury levels in hair of 6,600 subjects (4,400 of them women). In 2002, the Atlanta-based Centers for Disease Control and Prevention estimated that 1 in 6 U.S. women of childbearing age have enough mercury in her body to harm a developing fetus. Patch's study indicates that 1 in 5 women, or 25 percent more than previously estimated, have this level of mercury in their bloodstreams. Study subjects who ate eight or more servings of seafood per month had 0.9 parts per million of mercury in their hair. Subjects who ate no fish had only 0.06 parts per million, or 15 times less.

Source: Minnesota Women's Press - March 13, 2006

Computers utilized for quickly checking fish mercury levels. Pacific Seafood, a wholesale distributor in Sacramento, California became the first seafood processor in the nation to offer its customers the option of testing the level of mercury in the fish they purchase. The testing system, called Safe Harbor, was developed by Micro Analytical Systems Inc. The computer-based testing system makes it possible to quickly and affordably test fish for mercury levels before it leaves the processing plant on its way to grocery stores and restaurants. In addition, tested fish will be labeled to indicate that the fish has been tested and is below acceptable maximum levels. However, the exact amount of mercury tested is not available on the label but the amount allowed by the government is available on Safe Harbor's web site.

Source: Environmental News Network - March 2, 2006

Lead-Filled Mussels Unsafe Side Dish. Jakarta, INDONESIA -- The Jakarta administration has warned the public against eating green mussels farmed commercially in Cilincing and Muara Kapuk, both in North Jakarta, saying they are contaminated with toxic heavy metals. The lead and cadmium content of the mussels tested was 8.43 ppm and 1.11 ppm, respectively. The safe level is 0.4 ppm for lead and 0.1 ppm for cadmium. The mercury content was 0.01 ppm, lower than the normal level of 0.5 ppm. Data from the Jakarta Environmental Management Agency in 2005 showed the majority of Jakarta's 13 rivers were heavily polluted, mostly by industrial and household waste.

Source: Jakarta Post - March 13, 2006

Iowa Changes Fish Consumption Advisory System. Des Moines, IA -- The Iowa Department of Natural Resources (DNR) and Iowa Department of Public Health (DPH) used U.S. EPA guidance to develop a risk-based advisory system for Iowa that covers mercury, PCBs, and chlordane. Prior to 2006, contaminant levels in Iowa fish were compared to "action levels" for mercury, PCBs, and chlordane published by the U.S. Food and Drug Administration which has been abandoned in favor of a more protective "risk-based" approach. Based on the new advisory protocol, the DNR and DPH recommended the following:

. Cedar Lake in Cedar Rapids: Eat only one meal/week of common carp and channel catfish (chlordane and PCBs);
. Ottumwa Lagoons: Eat only one meal/week of channel catfish (chlordane);
. Nine Eagles Lake, Decatur County: Eat only one meal/week of largemouth bass (mercury);
. The Cedar River from the Highway 218 Bridge at Floyd (Floyd Co.) to the Iowa/Minnesota state line: Eat only one meal/week of smallmouth bass, walleye and northern pike (mercury);
. The Upper Iowa River from the Lower Dam in eastern Winneshiek County to the County Road W-20 bridge: Eat only one meal/week of small bass, walleye and northern pike (mercury);
. The Volga River and tributaries upriver from the town of Volga in western Clayton County: Eat only one meal/week of smallmouth bass (mercury).

Source: Waterloo Cedar Falls Courier - March 14, 2006

Are the Fish Safe to Eat? "It's Information, But You Make the Decision on Whether to Buy It or Not." Chattanooga, TN -- Signs posted by public health officials around waterways to warn people not to eat certain fish, or at least limit their consumption, raise many questions about the safety of eating fish. Representatives from the Fisheries for the Tennessee Wildlife Resources Agency and the Tennessee Division of Water Pollution Control explained that only the fish species named in the fishing guide are affected and all others should be considered safe. Most advisories in the Tennessee are immediately downstream from large metropolitan areas. There are some warnings for waters in and around Memphis. Some of the other significant warning includes Nickajack Lake downstream from Chattanooga, and Fort Loudon Lake just downstream from Knoxville. Public health officials also recommended procedures for cleaning fish, including remove and discard the belly flap and fatty strip along the backbone and lateral line, filleting the fish, and removing the skin.

Source: The Chattanoogan - March 14, 2006

Public Health's Annual Advisory Barely Changed. Bloomington, IL -- No new lakes or streams in Central Illinois were added to the annual fish advisory message issued by the Illinois Department of Public Health to limit exposure to fish contaminated with chemicals. Several area lakes and rivers remained on the list. They include:

. Lake Decatur for all sizes of carp and catfish;
. Powerton Lake channel catfish fro 15 to 19 inches are restricted to one meal a week. Channel catfish over 19 inches are restricted to one meal a month;
. White bass on the Illinois River are restricted to one meal a month from the headwaters to Starved Rock. Other restrictions refer to the Peoria pool;
. Meals of largemouth bass should be restricted to fish under 16 inches to one meal a week, bass 16 to 18 inches to six meals a year, and greater than 18 inches should not be eaten at all;
. Carp larger than 17 inches on the Mackinaw River should not be eaten more than once a week;
. Fish at specific locations added statewide this year include carp, channel catfish, crappie, white suckers, and sunfish;
. New rivers added include carp, catfish and smallmouth bass from the east branch of the DuPage River; carp from the Kankakee River, crappie, largemouth, spotted bass and carp from the Little Wabash; carp from Cedar Creek; channel catfish from Nippersink Creek, and carp from Spring Creek.

DNR said the recommendations are aimed at sensitive populations. Due to mercury contamination, all children, pregnant women, nursing mothers and women of child-bearing age have been advised against eating predator fish from anywhere in the state since 2002.

Source: Bloomington Pantagraph - March 23, 2006

Warning: Limit Meals of Local Flounder. Asbury Park, NJ -- Department of Environmental Protection officials said that people should not eat winter flounder caught in Raritan Bay and New York harbor waters more than once a month because the fish may have elevated levels of polychlorinated biphenyls (PCBs), a family of now-banned industrial chemicals believed to cause cancer. This is the first time any flounder species has been added to the advisory for PCBs.

Source: Asbury Park Press - March 24, 2006

Signage in South Warns of Fish Contamination. Malesso, GUAM -- Four advisory signs were installed in Malesso to warn about PCB contamination in Cocos Lagoon. The Guam Environmental Protection Agency plans to erect signs at Cocos Island and the Agat Marina. The precautionary warnings by the Guam EPA and Department of Health remain in effect until the U.S. Coast Guard performs further tests. Fish consumption should be limited and prepared by removing skin, fat and cooking thoroughly.

Source: KUAM.com - March 24, 2006

3M Chemicals in Mississippi Prompt New Fish Advisory. Minnesota, MN -- Researchers for the state and 3M found high levels of the perfluorochemical compound PFOS in fish in a stretch of the Mississippi River in the south Twin Cities metro area to issue new advisories for bluegill sunfish. Releases of PFOS came from the Scotchgard manufacturing operations at 3M's Cottage Grove plant, where the product was made for nearly 50 years. State health officials issued new recommendations advising against eating more than one meal of bluegill sunfish a week from "Pool 2" of the Mississippi River between the Hastings Dam and Ford Dam in Saint Paul.

Source: Public Radio - March 28, 2006

All Eyes on Lake Wabamun Spring Thaw Will Reveal Extent of Oil Damage. Edmonton, CANADA -- Melting ice on Lake Wabamun may result in more environmental damage from a train wreck and oil spill that occurred last summer. Last year's advisories warning residents not to eat fish and waterfowl in the area remain in effect as officials from Canadian National, Alberta Sustainable Resources and Capital Health await the spring thaw and prepare to reassess the health risks.

Source: Edmonton Sun - March 31, 2006

Delaware issues health advisories for popular fish. DELAWARE -- Officials toughened fish consumption warnings for some of the region's water bodies and most popular food fish, including hatchery-raised trout released to Delaware streams. Most of the expanded recreational fishing advisories are based on cancer risks from long-banned industrial pollutants still found in fish tissues. The first-ever freshwater trout warning is for polychlorinated biphenyls (PCBs). State scientists have identified hatchery fish food as a likely source for the toxic contaminant. Other advisories include sea trout (weakfish) taken from the Delaware River and Bay, and saltwater bluefish caught in the river, bay, Atlantic coast or inland bays.

Source: The News Journal - March 30, 2006

Tuna sushi from LA restaurants test high for mercury. Los Angeles, CA -- Investigators from Turtle Island Restoration Network and its GotMercury.Org program visited six of LA's top sushi restaurants and submitted samples of their tuna sushi to a laboratory for mercury testing. Results showed that tuna sushi contained an average mercury level of 0.721 parts per million (ppm), which approaches the levels of king mackerel, which the FDA instructs women of childbearing age and children never to eat. Public health analyst for GotMercury.Org suggested that FDA should immediately revise its March 2004 mercury in seafood advisory to clarify that women and children should stop eating almost all tuna. FDA data shows that fresh and frozen tuna average 0.383 ppm, about half the levels shown by GotMercury.Org's testing results. This differences could be due to the fact that sushi grade tuna often comes from the biggest, fattest tuna, subsequently may contain higher mercury levels.

Current Events, News and Journal Articles

Demographic and lifestyle factors associated with dioxin-like activity (CALUX-TEQ) in human breast milk in Hong Kong. Maternal exposure to dioxins and related compounds before conception may affect the health of the fetus. To identify factors affecting dioxin body load in Hong Kong, in 2002, total dioxin-like activity was estimated in 250 individual milk samples at 2-6 weeks postpartum, from a representative group of primiparous mothers, (mean age 29 +/- 5 years), by a chemically activated luciferase expression (CALUX) bioassay. Associations between the CALUX-TEQ and 20 socio-demographic and dietary variables were examined separately in mothers younger than 30 years (n = 114) and 30 years or older (n = 119), by multiple linear regression analysis. CALUX-TEQ significantly increased by 0.4-0.5 pg/g fat for every year of the mother's age. Mothers born in Guangdong province of China had a significantly higher CALUX-TEQ. Higher seafood consumption and having a female baby were associated with a higher maternal CALUX-TEQ level. Age was the strongest factor affecting human dioxin levels in Hong Kong. Birthplace and residence are important indicators of variations in exposure to environmental pollution in the Asia Pacific region. Temporal trends in body loads of dioxins remain to be established and continuous monitoring of dioxins in humans and foods is necessary as a precautionary approach to guide environmental control measures and prevent exposure to infants.

Dietary intake of differently fed salmon: a preliminary study on contaminants. In a previous study, a group of coronary heart disease patients exhibited positive cardioprotective effects of fatty acids derived from a diet of farmed Atlantic salmon fed fish oil. This follow-up study examines these patients for plasma exposure to selected organic and inorganic contaminants found in seafood that may detract from the benefits of eating oily fish. The study design was from Seierstad et al. (2005), where 58 patients were allocated into three groups consuming 700 g week(-1) of differently fed Atlantic salmon fillets for 6 weeks: 100% fish oil, 100% rapeseed oil, or 50% of each.

Different fillets showed graded levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (DLPCBs), indicator PCBs, polybrominated diphenyl ethers (PBDEs), and arsenic (As). Mercury (Hg) and lead (Pb) levels were similar across the three types of fillets. After 6 weeks of consumption, patient levels of PCDDs, DLPCBs, and PCBs in plasma decreased as the dietary intake of these contaminants increased. Plasma PBDEs only showed increases for the fish oil patients. Levels of inorganic contaminants in plasma showed only slight changes over the study period. These results show a reduction in the use of marine oils in fish feed reduces organic contaminant levels in farmed salmon while still providing a good dietary source of marine fatty acids.

Liquid chromatographic-cold vapour atomic fluorescence spectrometric determination of mercury species. Solvent extraction, sonication, and microwave-assisted extractions in the presence of extraction agents (thioacetic acid, citric acid, cysteine, 2-mercaptoethanol, HCl + NaCl, etc.) were tested for the isolation of mercury species. A mixture of 6 M HC1 and 0.1 M NaCl was selected as the most suitable extraction agent. The extraction efficiency was about 10% higher when microwave-assisted extraction was applied instead of sonication. The liquid chromatography-cold vapor atomic fluorescence spectrometry (LC/CV-AFS) method was optimized and used to separate and determine inorganic mercury cations and alkylated and arylated mercury species. Isocratic elution at a flow rate of 0.15 mL/min was used for separation of mercury species on a Hypersil BDS C18 RP column. The concentrations (2-10 mg/kg fresh weight) of total mercury and methylmercury in selected fish obtained by HPLC/CV-AFS were in good agreement but more precise than those determined by GC coupled to an electron capture detector.

Caudal fin mercury as a non-lethal predictor of fish-muscle mercury. The caudal (tail) fins from 17 walleye (Sander vitreus) and 12 northern pike (Esox lucius) from three northern Arizona lakes (Long Lake, Soldier Lake, and Upper Lake Mary) were analyzed for total mercury by combustion-atomic absorption spectrometry. Results indicate that the fin contains measurable mercury that correlates with muscle-mercury concentrations. As the body burden of mercury increased, the concentration in the fin increased relative to the muscle. Mercury concentrations also increased with fish length and weight, although the relationship was lake and species-dependent. Fish from Soldier Lake had the most efficient uptake of mercury, likely due to the trophic structure of the lake or the condition of the fish, but possibly due to an acute source of mercury. Overall, this study demonstrates that caudal fin clippings can be used as a non-lethal predictor of muscle-mercury concentrations, which can reduce the number of fish killed in routine monitoring programs.

Trace metal concentrations in edible tissue of snapper, flathead, lobster, and abalone from coastal waters of Victoria, Australia. The concentrations of heavy metals in the edible tissue of commonly fished species of the Victorian coast of Australia are reported. The metals studied were arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb), selenium (Se), and zinc (Zn). The fish species examined were snapper, flathead, lobster, and abalone. None of the fish species studied had average concentrations exceeding the maximum levels specified for As, Cd, Hg, and Pb by the Food Standards Australia and New Zealand Food Standards code. Additionally, the concentrations of Cu, Se, and Zn were close to or below the median values generally expected in these species. Essential trace elements Se and Zn were found to be well regulated by all fish species. Although also essential, Cu was not so well regulated, especially in abalone. Nonessential metals (As, Cd, and Hg) are not regulated in the studied fish and their concentrations in the fish tissue are dependent on size and fishing zone. Metal concentrations were not largely affected by sex. Surprisingly, the concentrations of metals in fish in Port Phillip Bay, a zone, which includes the major cities of Melbourne and Geelong and is known to have high concentrations of metals in the water and sediment, were not consistently higher than those in other less-populated fishing zones.

Too much of a good thing? Update on fish consumption and mercury exposure. While there is a significant amount of data showing health benefits of increased fish consumption, there are conflicting reports about the cardiovascular risks of mercury in seafood. A recent long-term study attempts to resolve this controversy, providing an opportunity to balance recommendations from the US EPA for mercury with those from the American Heart Association for fish consumption.

Persistent organic pollutants and metals in the freshwater biota of the Canadian Subarctic and Arctic: An overview. Over 1999-2002, a series of contaminant studies were conducted on freshwater biota of Canada's Arctic and Subarctic regions. The majority of inorganic contaminant studies focused on mercury in fish. While mercury concentrations were low in benthic feeding fish such as whitefish, predatory fish such as lake trout, pike, and walleye frequently had mercury levels which exceeded 0.2 mu g/g, the consumption guideline for frequent consumers of fish, and 0.5 µg/g, the guideline for the commercial use of fish. Numerous consumption advisories were issued for lakes along the Mackenzie River. Relatively high mercury levels appear to be due to relatively old fish populations and tend to be more prevalent in smaller lakes where warmer summer water temperatures and watershed influences result in greater mercury and methyl mercury inputs. Mercury levels were substantially lower in char than in lake trout, possibly due to a combination of a less fish-rich diet, a colder environment, and smaller methylmercury watershed inputs. Temporal trend monitoring has revealed little evidence of declining mercury levels in fish that can be attributed to declining atmospheric inputs. Because mercury follows complex pathways in the environment, other factors may counteract reductions in atmospheric mercury sources, e.g., climatic variability, changes in the commercial fishery, and interactions between fish species.

Most organochlorine (OC) investigations were based on long term trend monitoring and focused on char, burbot, and lake trout. There was strong evidence of declining OC concentrations in char, particularly Sigma HCH and Sigma chlordane, which may reflect a response to declining atmospheric inputs. Endosulfan concentrations increased, as in the atmosphere. There also was evidence of declining OC concentrations in burbot in the Slave and Mackenzie rivers but not in Great Slave Lake and Yukon lakes. OC concentrations decreased in lake trout in Yukon lakes in the 2000s, probably because of changes in the fish themselves (i.e., reduced lipid content, condition factor) and possibly climatic variability. Similarly, OCs declined in Great Slave Lake trout. New research on PDBEs and perfluorinated compounds determined that these contaminants are widespread in freshwater fish and concentrations may be increasing. Global warming is a major issue of concern for Arctic and Subarctic waters and may have adverse impacts on contaminant levels in fish and other biota. In addition, monitoring studies should be broadened to consider factors affecting other aspects of fish biology. Foremost among these is integrating contaminant monitoring studies on lakes with stock assessment studies. Ecosystem-based studies should be conducted to more effectively understand contaminant trends and should consider inputs (atmospheric, river inflow, resupension), losses (sedimentation, volatilization), and biological pathways.

A snapshot of PCB levels in Hoosic River sediments, crayfish and brown trout in the tri-state area. Levels of PCBs in river bank sediments, crayfish and brown trout were measured for samples taken from the Main and South Branches of the Hoosic River. Sample sites were principally in Massachusetts but included sites in Vermont and New York. The Hoosic is a fast flowing river, carrying sediment that is primarily fine sand (ca. 75%) mixed with silt and clay. Sediment samples were collected at 14 recreationally-relevant sites on a singe day in September 2003 to provide a snapshot of PCB levels that minimized variations caused by river level, flow rate, and other weather/season-dependent parameters. PCB contamination in the Hoosic originates at the site of the former Sprague Electric Company (SEC) plant in North Adams, MA where a capped waste dump has leaked Aroclors 1242 and 1254. Measurements of Aroclor 1254 show that the average surface sediment PCB level downstream of the SEC is 0.1 ppm, varying from 0.020 to 0.235 ppm. Subsurface sediments show the same average concentration but vary more widely, from 0.010 to 0.628 ppm. South Branch PCB levels, upstream of the SEC, are significantly lower but indicate the presence of a diffuse, low level source of PCB contamination on this section of the Hoosic. Crayfish contained levels of Aroclor 1254 that were significant but may signal a decline in PCB levels compared to previous studies. Brown trout 1-2 years old showed roughly equivalent amounts of both Aroclors, with levels ranging from 0.1 to 0.4 ppm (wet weight). Older trout (4-7 years old) showed significantly higher levels of Aroclor 1242 relative to 1254 (2-5:1) with total PCB contamination greater than 2 ppm, exceeding the U.S. EPA consumption guidelines. These results do not indicate a significant decline in PCB levels compared to earlier studies. They also imply that brown trout bioaccumulate PCBs differently than crayfish and that local bans on consumption of Hoosic river fish should remain.

Residues of total mercury and methyl mercury in eel products. Fifty-two samples of broiled eels and broiled eel liver were analyzed for total mercury and methyl mercury. The mean concentrations of total mercury in broiled eels and broiled eel liver were 0.21 ppm and 0.10 ppm, respectively. Meanwhile, the mean concentrations of methyl mercury in broiled eels and broiled eel liver were 0.085 ppm and 0.039 ppm, respectively. The rate of methyl mercury to total mercury mainly ranged from 60 to 80% in broiled eels and from 35 to 65% in broiled eel liver. The total mercury concentrations of 2 samples of broiled eels and one sample of broiled eel liver exceeded the provisional regulation limit (0.4 ppm) of total mercury in fish in Japan. In these samples, the rates of methyl mercury to total mercury were lower than 20%. The muscles and the skin of broiled eels were measured separately. The ratios of skin to muscle concentration of total mercury and methyl mercury were mainly in the range from 1/10 to 1/4. The mean intakes of total mercury from broiled eels and broiled eel liver per individual were 24.6 µg and 3.1 µg, respectively. The mean intakes of methyl mercury from broiled eels and broiled eel liver per individual were 10.4 µg and 1.2 µg, respectively.

A history of total mercury in edible muscle of fish from lakes in northern Canada. Subsistence fishing has been an important source of food for Native People in northern Canada since prehistoric time. Measurements of the levels of mercury in edible muscle of northern fish have been undertaken for over three decades to evaluate the risks of consuming northern fish. This report summarizes the data obtained from 7974 fish of 25 species from sites distributed from the Yukon to Labrador. The most abundant species were lake trout, lake whitefish, arctic char, walleye, northern pike and burbot. The results were used to support decisions on fishing and safe consumption of fish. They were sorted in several ways, into concentration ranges corresponding to human consumption guidelines, into political jurisdictions and into types of bedrock geology. Overall walleye, northern pike and lake trout, usually exceeded the subsistence consumption guideline of 0.2 µg g(-1) total mercury and often exceeded the higher guideline of 0.5 µg g(-1) total mercury for commercial sales of fish. Mercury in burbot, another facultative predator, was often lower but several still exceeded guidelines. Arctic char collections were mostly from anadromous populations and these had very low levels of mercury, presumably reflecting marine food sources. Lake whitefish were among the cleanest fish examined with 69 of 81 collections falling in the lowest range. Most collections were from sites in sedimentary rock. However a few sites were in metamorphic, intrusive or volcanic rocks. These, taken together, tended to have a higher proportion of sites in the higher ranges of mercury. These results indicate a widespread problem with mercury in subsistence fisheries for predator species of fish with the problem being most problematic for Nunavut.

Assessment of marine pollution in Izmir Bay: Nutrient, heavy metal and total hydrocarbon concentrations. Izmir Bay (western Turkey) is one of the great natural bays of the Mediterranean. Izmir is an important industrial and commercial centre and a cultural focal point. The main industries in the region include food processing, oil, soap and paint production, chemical industries, paper and pulp factories, textile industries and metal processing. The highest total hydrocarbon levels were found in the inner bay due to the anthropogenic activities, mainly combustion processes of traffic and industrial activities. The concentrations of heavy metals found in fish varied for mercury: 4.5-520, cadmium: 0.10-10 and lead: 0.10-491 µg kg(-1) in Izmir Bay. There was no significant seasonal variation in metal concentrations. An increase in Hg concentration with increasing length was noted for Mullus barbatus. Consumption of more than 2, 133 and 20 meals per week of fish in human diet would represent the tolerable weekly intake of mercury, cadmium and lead, respectively, in Izmir Bay. Heavy metal levels were lower than the results in fish tissues reported from polluted areas of the Mediterranean Sea.

Metal status of Nairobi River waters and their bioaccumulation in Labeo cylindricus. This study focused on the analysis of metals in water and fish from Nairobi River. Water from Kikuyu, Kawangware, Chiromo, Eastleigh, Njiru and Fourteen Falls along the Nairobi River was analyzed for the presence of metals. Most of the metal levels in water were below the critical limit of WHO and Kenya Bureau of Standards except lead, chromium, iron and manganese. Isolated cases of mercury and aluminum pollution were recorded. This study also analyzed metal levels in fish organs and tissues of fish caught from downstream (Fourteen Falls). The highest zinc concentration (360 µg/g) was in the scales, copper recorded the highest concentration in the kidney (45 µg/g), while cadmium recorded high values (167 µg/g) in the heart. Lead recorded high values (178 µg/g) in the heart and mercury recorded high values also in the heart (1000 ng/g). Most of these organs, are however, not eaten by man as food. Although metal levels were within normal levels in the water at Fourteen Falls, mercury, copper, lead and iron recorded higher than accepted levels in some fish organs. These results suggest that caution should be exercised in the consumption of fish from Fourteen Falls.

Biomonitoring of heavy metals and trace organics using the intertidal mussel Perna viridis in Hong Kong coastal waters. This paper presents the results of a 6-year (1998-2003) survey of trace toxics in the intertidal mussel P. viridis conducted by the Hong Kong Environmental Protection Department. Concentrations of heavy metals and trace organics were measured in the soft bodies of P. viridis collected from five sites in Hong Kong waters in order to establish the spatial patterns of contaminants in mussels. Among the metals analyzed, Cd showed a significant concentration gradient in Hong Kong waters. The levels of Cd in P. viridis were significantly higher at Ma Wan as compared to the other sites studied. Ma Wan also had relatively higher concentrations of Pb. Mn concentrations were particularly prominent at Wu Kai Sha. Significantly higher concentrations of Hg and Cu were recorded at Tai Tam and Tsim Sha Tsui. Tai Tam and Wit Kai Sha had higher levels of V; whereas higher Ni concentrations were recorded at Lamma Island and Tai Tam. No clear spatial patterns for Al, As, Cr, Fe and Zn were observed. Higher concentrations of PAHs in P. viridis were observed around urban centers impacted by sewage discharges, whereas higher PCB levels were found in less urbanized areas, suggesting that these may be due to non-sewage related inputs. The study also shows that Northwest and Southern waters are subject to a higher degree of DDT pollution compared with other sites. Of the 17 dioxin compounds analyzed, positive data were recorded for two compounds which are of low toxicity, whereas the most toxic congeners (i.e. 2,3,7,.8-TCDD and 1,2,3,7,8-PeCDD) were not detected during the study.

This study found that the levels of some highly toxic heavy metals (i.e. Cd, Hg and Pb) in P. viridis did not exceed the recommended limits for shellfish as food in Hong Kong (i.e. Cd: 2.0 ppm; Hg: 0.5 ppm; Pb: 6.0 ppm wet weight). The levels of As and Ni in P. viridis were also well below the action limits set by the US FDA (i.e. As: 86 ppm; Ni: 80 ppm wet weight). DDT and PCB contaminations in P. viridis were below the concentrations of concern. Compared with data obtained in the 1980s, the current levels of DDTs in P. viridis were 4-16 times lower. Lead concentrations have also been lowered significantly. These results are mainly related to reduction in local and regional pollution sources during the past 20 years.

Concentrations of trace elements in marine fish and its risk assessment in Malaysia. Concentrations of trace elements (V, Cr, Mn, Co, Cu, Zn, Ga, Se, Rb, Sr, Mo, Ag, Cd, Sn, Sb, Cs, Ba, Hg, Tl, Pb and Bi) were determined in muscle and liver of 12 species of marine fish collected from coastal areas in Malaysia. Levels of V, Cr, Mn, Co, Cu, Zn, Ga, Sr, Mo, Ag, Cd, Sri, Ba and Pb in liver were higher than those in muscle, whereas Rb and Cs concentrations showed the opposite trend. Positive correlations between concentrations in liver and muscle were observed for all the trace elements except Cu and Sn. Copper, Zn, Se, Ag, Cd, Cs and Hg concentrations in bigeye scads from the east coast of Peninsular Malaysia were higher than those from the west, whereas V showed the opposite trend. The high concentration of V in the west coast could indicate oil contamination in the Strait of Malacca. To evaluate the health risk to Malaysian population through consumption of fish, intake rates of trace elements were estimated on the basis of the concentrations of trace elements in muscle of fish and daily fish consumption. Some specimens of the marine fish had Hg levels higher than US EPA guidelines, indicating that consumption of these fish may be hazardous to Malaysian people.